This invention relates to pattern detection in a sequence of computer marks and spaces.
At present, a FIFO or similar device is used to store information about mark and space lengths. An error that occurs in such information will propagate and affect other device information downstream of the location where the error occurs.
What is needed is an approach that provides mark and space information but does not permit an error in such information to propagate much beyond the location where the error is first observed.
These needs are met by the invention, which provides a system that compares mark and space information immediately before a segment is received by a segment processor. Three consecutive segments, MK, PS and PM, are received by segment pre-processors, and the segment lengths, L(MK), L(PS) and L(PM), are determined. If one or another of these lengths is non-complying, the corresponding pre-processor optionally issues an error signal that is received by the processor before, or at the time that, the processor receives at least one of these three segments. The processor then compensates for, or corrects, a segment with a non-complying length.